1. Field of the Invention
The present invention relates to a sensor equipped wheel support bearing assembly, specifically a bearing for a vehicle wheel with a sensor, of a type having a load sensor built therein for detecting a load imposed on a bearing unit for a vehicle wheel.
2. Description of the Related Art
As a technique to detect a load imposed on each of vehicle wheels of an automotive vehicle, the sensor equipped wheel support bearing assembly has been suggested, in which the load is detected by detecting a strain occurring in a flange outer diametric surface of an outer ring, which is a stationary ring, of the wheel support bearing assembly. (See, for example, the Patent Document 1 listed below.) The wheel support bearing assembly of a type having a strain gauge pasted to an outer ring of the wheel support bearing assembly for detecting the strain has also been suggested. (See, for example, the Patent Document 2 listed below.)
Further, the sensor equipped wheel support bearing assembly has been suggested, in which a sensor unit made up of a strain generating member and a strain sensor fitted to this strain generating member is fitted to the stationary ring of the bearing unit, which strain generating member includes a contact fixing segment at least two locations relative to the stationary ring and has a cutout defined at least one location between the neighboring contact fixing segments, with the strain sensor arranged in this cutout. (See, for example, the Patent Document 3 listed below.)
According to the sensor equipped wheel support bearing assembly disclosed in the Patent Document 3, since when the load acts on a rotatable ring incident to travel of the automotive vehicle, the stationary ring is deformed through rolling elements, such deformation brings a strain in the sensor unit. The strain sensor provided in the sensor unit detects such strain in the sensor unit. If relations between strains and loads are determined beforehand by means of a series of experiments and/or simulations, the load or the like acting on the vehicle wheel can be detected from an output of the strain sensor.    [Patent Document 1] JP Laid-open Patent Publication No. 2002-098138    [Patent Document 2] JP Laid-open Patent Publication No. 2003-530565    [Patent Document 3] JP Laid-open Patent Publication No. 2007-057299